58 
DR. JOHN STENHOUSE ON THE NITROGENATED PRINCIPLES OF 
assumed, that “ whenever ammonia is generated in large quantity from complex, either 
animal or vegetable substances, it is always accompanied by the formation of a larger 
or smaller amount of volatile organic bases'" If therefore researches similar to the 
present are actively prosecuted, and if the seeds and leaves of the various genera of 
plants especially are subjected to these or similar processes, it seems not unreason- 
able to expect that the number of the volatile organic alkaloids will ere long be 
considerably increased. 
Another inference which M^e think maybe fairly deduced from these experiments is, 
that the nitrogenous principles of plants, viz. vegetable albumen, caseine, fibrine, &c., 
though very analogous, are not identical with the corresponding principles of the 
animal kingdom, otherwise the products of their decomposition would have been the 
same. The same series of bases would therefore have been obtained from both beans 
and bones, and so also from the other animal and vegetable substances. This, as we 
have seen, however, is not the case ; I should therefore be disposed to conclude that 
animal and vegetable fibrine, caseine, &c., though very analogous, are not identical 
substances, as has hitherto been supposed by some eminent chemists. 
In conducting the destructive distillation of animal and vegetable substances, the 
chief point to be attended to is to operate at as low a temperature as possible, for I 
have not unfrequently found that when the heat had been inadvertently raised too 
high the organic bases were almost entirely destroyed, and ammonia was conse- 
quently almost the only alkaline product. I strongly suspect, therefore, that in many 
cases a considerable portion of the ammonia obtained from the distillation of animal 
and vegetable substances is really derived from the destruction of organic bases. 
This will appear still more probable when we consider that the organic bases are 
more complex in their structure than ammonia, and that if we pass even the most 
stable of them once or twice through a tube filled with red-hot charcoal, they are 
almost entirely resolved into that alkali. And even when organic bases are strongly 
heated in contact with potash or soda, or when their aqueous solutions are simply 
boiled for any length of time, they always undergo partial decomposition, ammonia 
being an invariable product. 
I must again apologize for the imperfect state of this paper. It is however merely 
the first of a series, and will, I trust, be regarded as only preliminary to more mature 
investigations. 
Glasgow, Wth June, 1849. 
